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A Technical Guide for Wine Producers
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RECENT ARTICLES | WYNBOER HOME
VINPRO (SA) / WINETECH VINEYARD PRACTICE EVALUATION We would like to thank all participants and panels responsible for the evaluation. Special thanks to the convenors in the various districts for their contribution to the success of the competition.
1. INTRODUCTION
A total of 56 entries were received this year, compared to last year's 46 blocks. This represents an increase of approximately 22% in entries.
The blocks in each KWV district were evaluated by different judging panels, who are composed annually on a rotation basis. Direct comparisons between districts therefore have to be handled circumspectly. Evaluation takes place according to a precomposed evaluation form. This year, for the first time, the evaluation form also made provision for the evaluation of mechanised vineyards.
The cultivar type and number of blocks entered in the various KWV districts are indicated in table 1. A minimum of five entries per district are required to validate the evaluation. Figure 1 shows that compared to the 1998 entries, there is an increasing number of noble cultivars as a percentage of the number of entries per district.
Table 2 indicates the details of the winning blocks in the various KWV districts. It is particularly interesting to notice how the blocks vary with regard to choice of rootstock, plant width, trellis systems and how they are adapted to the specific region's climatic conditions and the wine goal.
The competition is judged in three categories. The judging form makes provision for long term techniques, short term techniques and general appearance.
2. LONG TERM TECHNIQUES
The practices evaluated under this heading are soil preparation, cultivar adaptation to the resources, condition, row direction, hereditary quality, spacing, trellis system, vine shape and irrigation system.
In the case of soil preparation, the soil potential, position and slope are taken into account. The profile holes (as prescribed by the rules of the competition) are studied by the judges and the efficiency of soil preparation is evaluated according to the root distribution, taking into account the soil potential.
Figure 2 shows how the judges evaluated soil preparation in the various districts. The Little Karoo (100%) in particular fared very well in this section, while Olifants River (97%), Worcester (88%), Robertson and Stellenbosch (83%) deserve special mention. In the Orange River (47%), Paarl (67%) and Malmesbury (67%) the correct way of soil preparation should definitely receive more attention. Although the blocks evaluated by the panels are not the same, points awarded this year for soil preparation were compared to those of 1998. It is good to see that the marks awarded for soil preparation increased in all the districts, except Orange River and Robertson, where they remained constant.
3. SHORT TERM TECHNIQUES
The practices evaluated under this heading are fertilisation, irrigation, winter pruning, foliage management, weed control and crop protection. Figure 3 shows that the points awarded for maintenance fertilisation, with the exception of the Little Karoo (90%), are very disappointing. In Olifants River (11%), Paarl (40%), Worcester (50%), Robertson and Malmesbury (54%), Orange River (58%) and Stellenbosch (65%) it will be very beneficial to pay attention to this practice. The same figure shows (when comparing the 1999 points to those of 1998) that there has been no real progress with regard to fertilisation, except in the Olifants River and Little Karoo districts.
Too little or too much fertilisation has an important effect on the vigour of vines and eventually also on the final quality of the grapes and wine. Except for the short term disadvantages of over-fertilisation (over-prolific growth, rot, etcetera), there are also long term disadvantages, such as infertility caused by foliage compaction.
The direct cost per hectare of fertilisation and the percentage of production cost per hectare, are as follows:
It is therefore obvious that over or under-fertilisation does not play a big role in the production cost per hectare, but that results should rather be quantified in the quality and therefore the selling price of wine.
4. GENERAL APPEARANCE
In this category growth vis à vis soil potential, uniformity of the block, appearance of the foliage during ripening with a view to wine quality, appearance of the crop during ripening and the overall appearance of the farm are evaluated.
A subsection which carries a lot of weight with regard to the allocation of points is the appearance of the foliage during ripening with a view to wine quality. The following aspects are evaluated:
Figure 4 shows that on average the regions did well in this section. The points allocated are as follows: Paarl (84%), Robertson (83%), Worcester (77%), Malmesbury (76%), Stellenbosch (75%), Little Karoo (68%), Olifants River (67%) and Orange River (65%).
5. SUMMARY
The best application of natural resources as well as the application of short and long term practices with a view to growing high quality wine grapes are the most important aspects to be evaluated. With the market requiring high quality wines and the growing demand for wines made from noble cultivars, the evaluation of viticultural practices is an excellent opportunity to obtain specialist opinions regarding your own viticultural practices. All participants receive the judging panel's comments so that they can make adjustments and improve their practices.
The evaluation also serves as an important extension aid, with annual workshops and farmers' days being held at the winning blocks in the various districts. While the correct application of the various practices is demonstrated and critically discussed, there are also discussions about other topical and relevant subjects regarding the cultivation of wine grapes.
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